NGC 2207 and IC 2163 are two spiral galaxies in the process of merging.

This pair contains a large collection of super bright X-ray objects called "ultraluminous X-ray sources" (ULXs).

Astronomers have found evidence for three supernova explosions within this pair in the past 15 years.

A new composite image of the system contains X-rays from Chandra (pink) along with optical and infrared data.

At this time of year, there are lots of gatherings often decorated with festive lights. When galaxies get together, there is the chance of a spectacular light show as is the case with NGC 2207 and IC 2163

Located about 130 million light years from Earth, in the constellation of Canis Major, this pair of spiral galaxies has been caught in a grazing encounter. NGC 2207 and IC 2163 have hosted three supernova explosions in the past 15 years and have produced one of the most bountiful collections of super bright X-ray lights known. These special objects — known as "ultraluminous X-ray sources" (ULXs) — have been found using data from NASA's Chandra X-ray Observatory.

As in our Milky Way galaxy, NGC 2207 and IC 2163 are sprinkled with many star systems known as X-ray binaries, which consist of a star in a tight orbit around either a neutron star or a "stellar-mass" black hole. The strong gravity of the neutron star or black hole pulls matter from the companion star. As this matter falls toward the neutron star or black hole, it is heated to millions of degrees and generates X-rays.

ULXs have far brighter X-rays than most "normal" X-ray binaries. The true nature of ULXs is still debated, but they are likely a peculiar type of X-ray binary. The black holes in some ULXs may be heavier than stellar mass black holes and could represent a hypothesized, but as yet unconfirmed, intermediate-mass category of black holes.

This composite image of NGC 2207 and IC 2163 contains Chandra data in pink, optical light data from the Hubble Space Telescope in red, green, and blue (appearing as blue, white, orange, and brown), and infrared data from the Spitzer Space Telescope in red.

The new Chandra image contains about five times more observing time than previous efforts to study ULXs in this galaxy pair. Scientists now tally a total of 28 ULXs between NGC 2207 and IC 2163. Twelve of these vary over a span of several years, including seven that were not detected before because they were in a "quiet" phase during earlier observations.

The scientists involved in studying this system note that there is a strong correlation between the number of X-ray sources in different regions of the galaxies and the rate at which stars are forming in these regions. The composite image shows this correlation through X-ray sources concentrated in the spiral arms of the galaxies, where large amounts of stars are known to be forming. This correlation also suggests that the companion star in the binary systems is young and massive.

Colliding galaxies like this pair are well known to contain intense star formation. Shock waves — like the sonic booms from supersonic aircraft — form during the collision, leading to the collapse of clouds of gas and the formation of star clusters. In fact, researchers estimate that the stars associated with the ULXs are very young and may only be about 10 million years old. In contrast, our Sun is about halfway through its 10-billion-year lifetime. Moreover, analysis shows that stars of various masses are forming in this galaxy pair at a rate equivalent to form 24 stars the mass of our sun per year. In comparison, a galaxy like our Milky Way is expected to spawn new stars at a rate equivalent to only about one to three new suns every year.

A paper describing these results has been accepted for publication in The Astrophysical Journal and is available online. The authors of the paper are Stefano Mineo of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; Saul Rappaport from the Massachusetts Institute of Technology (MIT) in Cambridge, MA; Alan Levine from MIT; David Pooley from Sam Houston State University in Huntsville, TX; Benjamin Steinhorn from Harvard Medical School in Boston, MA, and Jeroen Homan from MIT.

I love your pictures in my e-mail. The universe is so interesting and we only have a limited knowledge of it... Hopefully, I continue receiving your wonderful pictures from the outer space. Thanks for your fabulous work. My sincere congratulations for all you do.

Posted by Elizabeth Carrizo on Tuesday, 02.20.18 @ 13:12pm

The telescope changed the world view. This event is happening trillions of times . We will get to see all the phases.

Posted by Patrick Fitzgerald on Monday, 03.20.17 @ 10:36am

It is amazing how the science has help us to discover the deepest mysteries of the universe. It has helps us to understand a little bit of all this cosmos. I am 65 years old and I enjoy a lot all this knowledge and this kind of technical development is incredible... thanks to many work and intelligent people. Thank you so much.

Posted by Ricardo Calderón on Monday, 03.13.17 @ 10:53am

Remember, with this excellent information, you are forming the beginning of early Maps that may one day guide our race to the new horizons of intergalactic travel and colonization. Keep up the good work. Do one thing and do it the Best.

Posted by Roy Holland on Monday, 11.14.16 @ 18:12pm

Cool picture.

Posted by Sunby on Friday, 08.21.15 @ 21:04pm

Thanks this are splendid pictures from your powered observatories.

Posted by ispas on Wednesday, 03.4.15 @ 16:28pm

Breathtaking image Continuing with the observation, I am really curious whether or not in our lifetime we will be able to see the two eyes meet, or passing thru exchanging stars.

Posted by Jeng Lee on Thursday, 01.8.15 @ 17:39pm

It simply has to be seen to be believed. Thank you for this information about the richest and brightest part of the universe.

Posted by Laerte Alencastro Schmitt on Saturday, 12.27.14 @ 15:34pm

With the collision, shockwaves, and supernovas happening, how does it all affect any planets in the area? Does it change their rotation, orbit, seasons temperature, atmosphere etc.?

Posted by Barbara on Wednesday, 12.24.14 @ 08:25am

Who gone stop it?

Posted by Sommer Bernard on Monday, 12.22.14 @ 09:24am

Would the counter rotation of the two galaxies have any effect on the chance of the two merging into one super massive galaxy?

Posted by Ian S on Saturday, 12.20.14 @ 10:16am

Is there a link to the optical image of the NGC 2207 IC 2163 collision?

Posted by Carl Amundson on Thursday, 12.18.14 @ 10:21am

Thank you for the picture and all the information. I am 63 years old and ever since a child I been fascinated by the universe, but for some reason with this vision I can't stop thinking of the millions of life forms wishing, hoping, wondering if anyone will come to their aid. Help. I know that we can't, but I wish that we are able to save our human, animal and plant life before we find ourselves in the same predicament they do. The view in every kind of waves are great but I wish there was a way we were able to help. Thanks again and great job.

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